The present invention relates to an automatic control system for prime movers such as an internal combustion engine for automatic vehicles, and more particularly to an automatic control system for prime movers for automatically effecting start of the prime mover in response to operation of a starting mechanism such as a clutch pedal and maintaining the prime mover in its operative condition when the vehicle is moving and for automatically effecting stop of the prime mover when the vehicle is arrested.
In such automatic control systems for prime movers as described above, a setting switch is arranged to be operated after the starter switch is actuated for making the control system operative. In use of the automatic control system, it is, however, presumable that if there occurs a malfunction of the setting switch and its related portion, the automatic start and stop control of the prime mover is effected in response operation of the starter switch without any intention of the operator. Under such a condition, the operator will be involved in unexpected stop and start of the prime mover in his driving operation, and it is impossible to render such automatic control of the prime mover ineffective without repair of the setting switch.